Merge pull request #3726 from dgquintas/iomgr_executor

BUILD

Makefile

binding.gyp

build.yaml

gRPC.podspec

src/core/iomgr/closure.c

src/core/iomgr/closure.h

src/core/iomgr/executor.c

src/core/iomgr/executor.h

src/core/iomgr/resolve_address_posix.c

src/core/iomgr/resolve_address_windows.c

src/core/surface/init.c

test/core/iomgr/resolve_address_test.c

tools/doxygen/Doxyfile.core.internal

tools/run_tests/sources_and_headers.json

vsprojects/vcxproj/grpc/grpc.vcxproj

vsprojects/vcxproj/grpc/grpc.vcxproj.filters

vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj

...jects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters